北秦岭太白岩体岩石谱系单位划分及侵位时代确定  

Subdivision of rock series units and determination of intrusion age of Taibai rock mass in North Qinling

作　　者：校培喜[1] 张俊雅 王洪亮 雷鸿晏 

机构地区：[1]国土资源部西安地质矿产研究所,西安710054 [2]陕西地勘局区域地质矿产研究院,咸阳712000

出　　处：《西北地质科学》2000年第2期37-45,共9页Northwest Geoscience

基　　金：1∶5万磨房沟幅、太白梁幅区调部分成果

摘　　要：北秦岭太白岩体位于商丹构造带北侧 ,为不同时代形成的复式深成岩体。通过 1:5万区域地质填图将该岩体共划分为 7个岩石谱系单位 ,厘定为 2个超单元 ,即北部的五里峡超单元和南部的红崖河超单元 ,依据同位素测年结果和超单元间相互关系 ,确定五里峡超单元主体侵位时代为志留纪 ,红崖河超单元侵位时代为三叠纪。从岩体周边到中心 ,从北到南 ,侵位时代从早到晚 ,显示半环带状侧向推挤迁移侵位型式。岩石地球化学资料研究证明 ,五里峡超单元形成于活动陆缘火山弧构造环境 ,岩浆源于中上地壳 ;红岩河超单元形成于同碰撞构造环境 ,岩浆源于中下地壳。Taibai rock mass lying in the northern Shangxian Danfeng structural belt in North Qiling is a deep and multiple rock body formed in different ages It is divided into 7 rock series units and 2 super units based on regional geology mapping at 1∶50000 scale According to the isotopic dating and the relationship between the 2 super units, the main intrusion age of Wulixia super unit in the north is determined in the Silurian Period; and that of Hongyahe super unit in the south is determined in the Triassic Period The intrusion is from edge to centre and through the north to the south;and, accordingly,the intrusion age is from early to late as well The intrusion type shows a semicircular belt and lateral displacement Proven by the study of rock geochemistry data, Wulixia super unit formed in the volcanic arc structural environment of active continental margin and its magma derived from the middle upper crust;Whereas,Hongyahe super unit produced in the simultaneous collision structural environment and its magma derived from the lower middle crust

关 键 词：北秦岭 太白岩体 岩石谱系单位 侵位时代 

分 类 号：P588[天文地球—岩石学]